1. Field of the Invention
The present invention relates in general to vaporizing and concentration drying apparatus and method and, more particularly, to an improvement in such apparatus and method for recovering and reusing evaporation heat by means of liquidizing at a high temperature, that is, latent heat occurred in the process of vaporization reducing or increasing the pressure so as to save heating energy, and for oxidizing or carbonizing the vaporized impurities, such as odor, B.O.D. and C.O.D. laden in the vapor, at a high temperature so as to remove the vaporized impurities and to provide good quality of condensed water.
2. Description of the Prior Art
In conventional vaporizing apparatus, cooling water for condensing of vapor should be added to the apparatus along with the required heat for vaporization, that is, boiling heat (100 Kcal) and evaporation heat (latent heat of vaporization, 539 Kcal/l). In the case of distilled water which is prepared by vaporization and condensation of wet material, such as wet sludge or waste water, using the above vaporizing apparatus, a part of environmental polluting impurities, such as odor, B.O.D. and C.O.D., laden in the wet material is vaporized along with the vapor, thus to be laden in the vapor. The impurities laden in the vapor in turn are liquidized along with the vapor when condensing the vapor. The distilled water thus can not achieve allowable standard quality of water, so that the distilled water needs to be retreated in order to achieve the allowable standard quality.
The typical vaporizing apparatus as well as the typical vaporizing method can not recover and reuse the latent heat of vaporization (539 Kcal/l) of the vapor, but discard the latent heat through a condenser system used in cooling and condensing the vapor laden with impurities. Furthermore, such discarding of the latent heat should be accompanied by considerable cost.
Additionally, the typical vaporizing apparatus or the typical vaporizing method can not remove the impurities, such as odor, B.O.D. and C.O.D., which impurities are vaporized and liquidized along with the vapor and reduce the quality of the distilled water. In this regard, the distilled water should be treated through an additional water purifying procedure so as to improve the quality of the distilled water. The additional water purifying procedure for improving the quality of the distilled water is very complicated and increases the cost for preparation of the distilled water.
When water is vaporized using a pressure reducing vaporizing method so as to become steam, the evaporation heat can be saved by the amount of reduced pressure according to degree of vacuum. However, this pressure reducing vaporizing method still has a problem that the condensed water is laden with odor, B.O.D. and C.O.D., so that the condensed water needs to be treated through additional procedure for deodorization and for water purification.
In the typical heating vaporizing apparatus, the total heat for vaporizing 1 l of water of 0.degree. C. at atmospheric pressure is 639 Kcal. That is, the boiling heat for boiling the water at 100.degree. C. is 100 Kcal and the evaporation heat for vaporizing the boiled water is 539 Kcal, so that the total heat for vaporizing 1 l of water is 639 Kcal, that is, 100 Kcal+539 Kcal=639 Kcal. When vaporizing 1 l of water of 0.degree. C. using pressure reducing vaporizer, the water is boiled at 35.degree. C. under the condition that the degree of vacuum is about 10 Torr (750 mmHg), so that the total heat for vaporizing 1 l of water is 605 Kcal, that is, 35 Kcal+570 Kcal=605 Kcal (latent heat may be about 570 Kcal when vaporizing pressure is 0.1 kg/cm.sup.2.A).
However, the typical vaporizing apparatus should use a condenser for condensing and liquidizing the vapor, so that large amount of cooling water for condensing should be added to the apparatus. Furthermore, the latent heat (539 Kcal) of the vapor can not be recovered and reused, but discarded.
Briefly described, when vaporizing 1 l of water of 0.degree. C. at atmospheric pressure using either the typical pressure reducing vaporizing method or the typical heating vaporizing method, the total heat to be applied to the water is 574 Kcal or 639 Kcal. Furthermore, additional energy for supplying the cooling water of the condenser should be applied to the apparatus. In the process of condensing the vapor, the latent heat (539 Kcal) of vaporization can not be recovered but discarded. In addition, the typical vaporizing apparatus itself can not remove the environmental polluting impurities, such as odor, B.O.D. and C.O.D., from the condensed water, so that the condensed water needs to be treated through additional procedure for deodorization and for water purification.